1. Field of the Invention
This invention relates generally to a semiconductor technique and more particularly to a silicone polymer film or oxide film used as an insulation film on a semiconductor substrate, which is formed by using plasma CVD (chemical vapor deposition).
2. Description of the Related Art
In the plasma chemical vapor deposition method (plasma CVD method), deposition of a film on semiconductor substrates is conducted by placing each semiconductor substrate, being a processing target, on a resistance-heating type heater preheated to 0 to 350° C. in an atmosphere of 1 to 10 Torr. This heater is placed in a manner facing a shower plate that releases reactant gas, and high-frequency power of 13.56 MHz to 60 MHz, etc., is applied by 100 to 4,000 W to the shower plate to cause high-frequency discharge between the heater and shower plate and thereby generate plasma. The plasma CVD method is used to deposit various types of thin film, such as an interconnect insulation film, passivation film, and anti-reflection film. Since achieving a disproportionately high level of surface diffusion is difficult with parallel-plate type plasma CVD, high-density plasma CVD that uses microwaves has traditionally been used to form an oxide film, etc., having filling characteristics. These techniques have been used since the days of 250-nm device nodes. One feature of such apparatus is that it not only forms a film, but also performs etching of a film, which means that the apparatus can support smaller hole diameters. With current products having device nodes of 65 nm to 90 nm, the mainstream processing method is one that combines film formation and etch-back. Representative processes in which this method is used include STI (Shallow Trench Isolation), and upper-layer processing in the wiring process.
However, combination of film formation and etch-back will not likely support smaller device nodes of 60 nm and below, and there is a need for an insulation film offering sufficient filling characteristics in line with the accelerating trend for super-fine circuitry.